Respiratory System Trivia
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99 free Respiratory System trivia questions with answers — science & nature quiz, new questions added Oct 2026.
This respiratory system trivia quiz follows a breath from the nose to the bloodstream. It starts with the parts every biology class covers: the pharynx and its three sections, the larynx and its nine cartilages, the leaf-shaped epiglottis, the windpipe with its C-shaped rings, the two main bronchi and the lobes of the lungs. Then it goes smaller, into the alveoli, the type II cells that make surfactant, and the hemoglobin that carries oxygen away. The easy questions ask how many lobes each lung has and which muscle does most of the breathing. The harder ones ask which nerve roots supply the diaphragm, how many rings of cartilage the trachea has, why aspirated food tends to land in the right lung, what 'asthma' meant in Greek, and who identified the tuberculosis bacillus in 1882. There is a round on breathing itself: tidal volume, dead space, what inhaled air is made of and why hiccups happen. If you want the rest of the body, our human body, circulatory system and digestive system quizzes carry on from here. Every answer was checked against the encyclopaedia entry for the organ, disease or person before publishing, and the sentence that supports it is stored with each question.
30 of 99 questions with answers and explanations. Play the quiz
Q 01The left lung is the smaller one, to leave room for which organ?
Heart
Heart. It sits left of centre and fits into a dent in the left lung called the cardiac notch, so that lung holds less air than its shorter, wider partner.
Q 02Which blood cells pick up oxygen in the lungs and carry it to the rest of the body?
Red blood cells
Red blood cells. They have no nucleus and no mitochondria, so they burn none of the oxygen they carry and can deliver every bit of it to the tissues.
Q 03What is the common name for the trachea?
The windpipe
The windpipe. If the throat above it is blocked, a surgeon can cut a small hole into it at the front of the neck, a tracheostomy, and the patient breathes through a tube there.
Q 04Which first-aid technique, named for an American surgeon, uses abdominal thrusts to clear a choking person's airway?
The Heimlich maneuver
The Heimlich maneuver. Henry Heimlich described it in 1974, and in 2016, aged 96, he said he had used it himself to save a choking woman at his retirement home.
Q 05What shape are the cartilage hoops of the trachea?
Incomplete and C-shaped
Incomplete and C-shaped. The gap at the back is bridged by a muscle that tightens during a cough, narrowing the tube to help force the air out.
Q 06Where does the trachea end by splitting into the two main bronchi?
At the carina
At the carina. The lining of this ridge is the most cough-sensitive spot in the airway, so anything that lands on it sets off violent coughing.
Q 07Which birds did coal miners carry underground because carbon monoxide knocks them out before it harms a human?
Canaries
Canaries. Their rapid breathing and small bodies make them succumb first, which gave miners time to get out; Britain only decided to replace its pit canaries with electronic detectors in 1986.
Q 08If a foreign body is inhaled, where does it usually lodge?
Right main bronchus
Right main bronchus. It is wider, shorter and more upright than the left one, so an inhaled peanut or bead usually drops straight into it.
Q 09Approximately how many alveoli does a typical pair of human lungs contain?
About 480 million
About 480 million. That is an average: counts in six adult lungs ran from 274 to 790 million, because bigger lungs hold more alveoli rather than bigger ones.
Q 10The word 'alveolus' comes from Latin meaning what?
Little cavity
Little cavity. English borrowed the word in 1706 for a tooth socket and only later extended it to the lung's air sacs, which is why dentists still talk about alveolar bone.
Q 11Which alveolar cells release pulmonary surfactant?
Type II
Type II. They cover only a few percent of the alveolar wall, the rest being flat type I cells, yet without their secretion the air sacs would collapse with every breath out.
Q 12What does pulmonary surfactant do to the fluid lining the alveoli?
Reduces its surface tension
Reduces its surface tension. Water in the lining clings to itself and resists stretching, so without this slick coating the wet air sacs would be far harder to inflate.
Q 13Insufficient surfactant in preterm babies causes which condition?
Infant respiratory distress syndrome
Q 21Which nerve, formed from roots C3 to C5, supplies the main breathing muscle?
The phrenic
The phrenic. Irritate it and you get stubborn hiccups; lose both sides, as a high spinal injury can cause, and a person may need a ventilator to breathe.
Q 22During inhalation, which way does the main breathing muscle move as it contracts?
Downward toward the abdomen
Downward toward the abdomen. As the dome flattens, the chest cavity grows and the pressure inside drops below that of the air outside, so air flows in to fill the lungs.
Q 23A hiatus hernia is when part of the stomach pushes through which structure?
The diaphragm
Infant respiratory distress syndrome. Doctors now deliver replacement surfactant straight into the baby's airway, and steroids given to the mother before an early birth speed up the lungs' own supply.
Q 14What is the larynx commonly called?
The voice box
The voice box. Rest a finger on the front of your neck and swallow: you will feel it ride upward, a lift that helps close off the airway while food goes past.
Q 15A boy's voice breaks and deepens at puberty because his vocal cords do what?
Lengthen and thicken
Lengthen and thicken. Like a thicker rubber band, longer and heavier cords give a deeper note, and the cracks and squeaks come while the body adjusts to their new size.
Q 16Which laryngeal cartilage forms the Adam's apple?
Thyroid
Thyroid. The name is Greek for 'shield-shaped', and this shield grows and juts forward at puberty under testosterone, which is why the bump usually shows more on a man's neck.
Q 17Which leaf-shaped flap stops food and water entering the trachea?
The epiglottis
The epiglottis. It stands upright while you breathe, then folds back over the airway as the throat lifts during a swallow, steering the mouthful toward the stomach instead.
Q 18Pertussis is the medical name for which childhood infection, known for the gasp for air that ends each attack?
Whooping cough
Whooping cough. The 'whoop' is the sound of a child dragging air back in after a long bout of coughing, and the illness lingers so long it is also called the 100-day cough.
Q 19Which lumps of tissue behind the nose, often removed in childhood, are formally called the pharyngeal tonsils?
The adenoids
The adenoids. They swell through early childhood, when they can block the nose and force a child to breathe through the mouth, then shrink away and have usually vanished by adulthood.
Q 20Which passage links the middle ear to the back of the nose?
The auditory tube
The auditory tube. Better known as the Eustachian tube, it stays shut until a swallow or yawn opens it for a moment to even out the air pressure, and that is the pop you feel on a plane.
The diaphragm. The stomach squeezes up through the hiatus, the opening that normally lets the food pipe through, and the bulge lets acid escape upward, which is why heartburn is the classic symptom.
Q 24Which disorder makes breathing stop and restart again and again through the night, often with loud snoring?
Sleep apnea
Sleep apnea. The airway closes or blocks until the sleeper restarts with a snort or gasp, and in bad cases that happens 30 or more times an hour.
Q 25For how many years did Guinness record-holder Charles Osborne have hiccups?
68
68 years. They started in 1922 as he handled a hog for slaughter and stopped one morning in 1990; in between he married twice and fathered eight children.
Q 26What is the scientific name for a hiccup?
Singultus
Singultus. The Latin word means a sob: a jerk of the main breathing muscle sucks air in, and the throat snaps shut on it a split second later to make the 'hic'.
Q 27What is a pneumothorax, in which leaked air builds up inside the chest, more commonly called?
A collapsed lung
A collapsed lung. The escaped air presses on the lung from outside so it cannot fully expand; it can strike with no injury at all, and tall, thin people and smokers are more at risk.
Q 28ACHOO syndrome makes some people sneeze the moment they step out into what?
Bright sunlight
Bright sunlight. Aristotle blamed the sun's heat on the nose, but Francis Bacon faced the sun with his eyes shut and did not sneeze, which pointed to the eyes; doctors call it the photic sneeze reflex.
Q 29What is the fluid-lined space between the two membranes that wrap each lung called?
The pleural cavity
The pleural cavity. Its thin film of fluid lets the lungs glide as you breathe, and when the membranes inflame and rub instead, every breath brings the sharp pain of pleurisy.
Q 30Which layer of the lung's double membrane covers the lung itself?
Visceral
Visceral. This inner layer has no pain nerves, so the stabbing ache of an inflamed chest lining comes from the outer layer that lines the ribs.